U.S. patent number 7,546,398 [Application Number 11/461,461] was granted by the patent office on 2009-06-09 for system and method for distributing virtual input/output operations across multiple logical partitions.
This patent grant is currently assigned to International Business Machines Corporation. Invention is credited to Karyn T. Corneli, Christopher J. Dawson, Rick A. Hamilton, II, Timothy M. Waters.
United States Patent |
7,546,398 |
Corneli , et al. |
June 9, 2009 |
System and method for distributing virtual input/output operations
across multiple logical partitions
Abstract
The Distributed Virtual I/O Tool replaces dedicated VIO server
LPARs by distributing the virtual I/O functions across several
application LPARs connected by a high-speed communication channel.
The physical I/O devices are distributed across available LPARs.
The Distributed Virtual I/O Tool assigns each I/O request to an
appropriate I/O device. The Distributed Virtual I/O Tool monitors
each I/O request and reassigns I/O devices when performance drops
on a specific device or when a device is no longer available.
Inventors: |
Corneli; Karyn T. (Austin,
TX), Dawson; Christopher J. (Arlington, VA), Hamilton,
II; Rick A. (Charlottesville, VA), Waters; Timothy M.
(Hiram, GA) |
Assignee: |
International Business Machines
Corporation (Armonk, NY)
|
Family
ID: |
39054646 |
Appl.
No.: |
11/461,461 |
Filed: |
August 1, 2006 |
Prior Publication Data
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|
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Document
Identifier |
Publication Date |
|
US 20080126579 A1 |
May 29, 2008 |
|
Current U.S.
Class: |
710/38;
712/26 |
Current CPC
Class: |
G06F
9/5088 (20130101); G06F 11/2005 (20130101); G06F
11/3485 (20130101); G06F 11/2017 (20130101); G06F
2201/81 (20130101) |
Current International
Class: |
G06F
3/00 (20060101) |
Field of
Search: |
;710/38 |
References Cited
[Referenced By]
U.S. Patent Documents
Primary Examiner: Tsai; Henry W. H.
Assistant Examiner: Mamo; Elias
Attorney, Agent or Firm: Yee & Associates, P.C.
Steinberg; William H. Siegesmund; Rudolf O.
Claims
What is claimed is:
1. A method for accessing a plurality of input/output (I/O) devices
physically distributed across a plurality of logical partitions
(LPARs) without a single point of failure comprising: creating a
distributed virtual input/out (VIO) server by running a VIO tool on
each LPAR of the plurality of LPARs; wherein each LPAR is operable
to access the plurality of I/O devices using inter-partition
communication and each LPAR is operable to access an I/O device to
which it is directly connected; wherein each LPAR is mapped to a
dedicated I/O device that is not shared with the plurality of
LPARs; wherein each VIO tool performs steps comprising: receiving
an I/O request from an application by a VIO tool; assigning the I/O
request to one of the plurality of I/O devices, wherein the I/O
request is assigned to any I/O device of a proper type attached to
any LPAR, regardless of which LPAR runs the application; wherein
types of I/O devices comprise Ethernet adaptors, disk adaptors,
fibre channels and persistent storage media; accessing an I/O
Device Mapping List, that maps applications and LPARs to the
plurality of I/O devices using bindings; consulting an Autonomic
Manager to assign the I/O request to a preferred I/O device,
wherein the preferred I/O device is one performing at an acceptable
level; sending the I/O request to the assigned I/O device; binding
the I/O request to the assigned I/O device wherein an assignment of
the assigned I/O device is encapsulated in one or more subsequent
requests of a client/server session; saving the assignment to the
I/O Device Mapping List; responsive to a failure of a previously
assigned I/O device or to a failure of the LPAR mapped to the I/O
device, reassigning one or more subsequent I/O requests in the
client/server session to another I/O device; and saving the
reassigned I/O request to the I/O Device Mapping List; wherein a
plurality of input/output (I/O) devices physically distributed
across a plurality of logical partitions (LPARs) are accessible
without a single point of failure.
Description
FIELD OF THE INVENTION
The invention relates generally to electrical computers and digital
data processing, and specifically to selecting a path via which the
computers will transfer data.
BACKGROUND OF THE INVENTION
The advent of logical partitions ("LPARs") in UNIX servers enabled
mid-range servers to provide a class of service previously provided
only by mainframe systems. Mainframe computers traditionally used
physical partitioning to construct multiple "system images" using
separate discrete building blocks. UNIX servers, using logical
partitions, permitted finer granularity and interchangeability of
components across system images. In addition, the virtualization of
input/output ("I/O") devices across multiple partitions further
enhanced logical partitioning functionality. Virtualization of I/O
devices allows multiple logical partitions to share physical
resources such as Ethernet adapters, disk adapters and so forth.
Therefore, rather than dedicating these virtual I/O adapters to
each logical partition, the adaptors are shared between partitions,
where each LPAR uses only the I/O adaptors as needed.
Management of virtual I/O adapters requires a dedicated component
acting on behalf of all resources. For example, a Virtual I/O
server, or "VIO" server, may be created by forming a specialized
LPAR dedicated to the task of possessing all shared I/O devices.
The VIO server acts as a "virtual device" that fields input-output
requests from all other LPARs. All of the shared I/O devices are
physically attached to the VIO server. The IBM BladeCenter
approaches virtual I/O management differently using a BladeCenter
chassis that allows a virtual I/O to include fibre channel and
Ethernet networking interface cards. While the BladeCenter does not
rely on a dedicated LPAR to perform the virtualization, a dedicated
processor is housed in the management blade of the chassis, that
uses a dedicated VIO server to perform the virtualization.
Virtual I/O servers use software to seamlessly redirect
input/output to an alternate device if a first device fails. By
having access to multiple Ethernet adapters, for instance, the
failure of any single physical adapter no longer deprives any given
LPAR of Ethernet functionality. Instead, the VIO server provides
the desired functionality to its client LPAR from another physical
adapter.
The use of a central dedicated VIO server, however, puts all LPARs
into a state of extreme dependence upon that single dedicated VIO
server. For instance, if any failure mechanism, such as a processor
problem or an operating system malfunction, manifests itself on the
VIO server, all applications running on LPARs dependent upon that
VIO server lose their ability to communicate through the I/O
adaptors. In other words, the dedicated VIO server now becomes a
single point of failure for all applications and LPARs using I/O
adaptors.
One known solution to eliminate the single point-of-failure for a
VIO server is to create redundant dedicated VIO LPARs. However,
creation of redundant dedicated VIO LPARs unnecessarily consumes
resources. For instance, each dedicated VIO LPAR requires processor
and memory allocation, as well as disk space and other such
resources, which would better be used running applications and
performing direct value-added computations for users. Therefore, a
need exists for a distributed VIO server that can operate across
some or all of the application LPARs so that it is not subject to a
single point of failure and that also does not duplicate computer
resources.
SUMMARY OF THE INVENTION
The invention meeting the need identified above is the Distributed
Virtual I/O Tool. The Distributed Virtual I/O Tool replaces
dedicated VIO server LPARs by distributing the virtual I/O
functions across several application LPARs connected by a
high-speed communication channel. The Distributed Virtual I/O Tool
receives an I/O request for an application running on a logical
partition of a shared resource with a plurality of logical
partitions, wherein I/O devices are physically distributed across
the plurality of logical partitions. The Distributed Virtual I/O
Tool assigns the I/O request to one of the I/O devices, wherein the
I/O request can be assigned to any I/O device of the proper type
attached to any logical partition, regardless of which logical
partition runs the application receiving the I/O request, and sends
the I/O request to the assigned I/O device.
Generally, each application or LPAR maps to a specific I/O device,
binding the application or LPAR to the mapped device. If there is
not a prior assignment, the Distributed Virtual I/O Tool assigns an
I/O device when the I/O request is made. The Distributed Virtual
I/O Tool monitors each I/O request and reassigns I/O devices when
performance drops on a specific device or the LPAR connected to the
device is no longer available. Assignment and reassignment of an
I/O device may be based on the recommendation of an autonomic
manager tasked with monitoring and managing the performance of the
entire computer system. An alternate embodiment of the Distributed
Virtual I/O Tool queries each I/O device manager for availability
and performance data, and assigns or reassigns I/O devices based on
the responses of the I/O device managers. Alternatively, the
physical I/O devices may be distributed randomly across available
LPARs such that LPARs with specific I/O needs may be given priority
for a physical I/O device. In a further embodiment, a LPAR may have
a dedicated I/O device, and will not share the Virtual I/O
Tool.
The novel features believed characteristic of the invention are set
forth in the appended claims. The invention itself, however, as
well as a preferred mode of use, further objectives and advantages
thereof, will be understood best by reference to the following
detailed description of an illustrative embodiment when read in
conjunction with the accompanying drawings, wherein:
FIG. 1 is an exemplary computer network;
FIG. 2 is a diagram of an exemplary shared resource with a
dedicated VIO LPAR;
FIG. 3 is a diagram of a shared resource with a distributed VIO
tool;
FIG. 4 describes programs and files in a memory on a computer;
FIG. 5 is a flowchart of an I/O Management Component;
FIG. 6 is a flowchart of an I/O Device Assignment Component;
and
FIG. 7 is a flowchart of an I/O Failover Component.
DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT
The principles of the present invention are applicable to a variety
of computer hardware and software configurations. The term
"computer hardware" or "hardware," as used herein, refers to any
machine or apparatus that is capable of accepting, performing logic
operations on, storing, or displaying data, and includes without
limitation processors and memory; the term "computer software" or
"software," refers to any set of instructions operable to cause
computer hardware to perform an operation. A "computer," as that
term is used herein, includes without limitation any useful
combination of hardware and software, and a "computer program" or
"program" includes without limitation any software operable to
cause computer hardware to accept, perform logic operations on,
store, or display data. A computer program may, and often is,
comprised of a plurality of smaller programming units, including
without limitation subroutines, modules, functions, methods, and
procedures. Thus, the functions of the present invention may be
distributed among a plurality of computers and computer programs.
The invention is described best, though, as a single computer
program that configures and enables one or more general-purpose
computers to implement the novel aspects of the invention. For
illustrative purposes, the inventive computer program will be
referred to as the "Distributed Virtual I/O Tool"
Additionally, the Distributed Virtual I/O Tool is described below
with reference to an exemplary network of hardware devices, as
depicted in FIG. 1. A "network" comprises any number of hardware
devices coupled to and in communication with each other through a
communications medium, such as the Internet. A "communications
medium" includes without limitation any physical, optical,
electromagnetic, or other medium through which hardware or software
can transmit data. For descriptive purposes, exemplary network 100
has only a limited number of nodes, including workstation computer
105, workstation computer 110, server computer 115, and persistent
storage 120. Network connection 125 comprises all hardware,
software, and communications media necessary to enable
communication between network nodes 105-120. Unless otherwise
indicated in context below, all network nodes use publicly
available protocols or messaging services to communicate with each
other through network connection 125.
A computer with multiple logical partitions, known as a shared
resource, is shown in FIG. 2. Shared Resource 200 is an example of
the prior art method of providing a VIO server on a dedicated
logical partition, or LPAR. Shared Resource 200 has several LPARs
connected by Inter-Partition Communication 220, a high-speed
communication system linking all the LPARs, such as the POWER
HYPERVISOR product from IBM. LPAR_1 211 runs applications on an AIX
operating system. LPAR_2 212 runs applications on a LINUX operating
system. LPAR_3 213 runs applications on an i5 operating system.
LPAR_4 214 has unassigned resources available for increases in
demands for computing resources. LPAR_5 215 is the VIO LPAR and
physically connects to all the available I/O devices such as
Ethernet adaptors, fibre channels and persistent storage media.
Each application LPAR (211-214) accesses I/O devices 250 via
Inter-Partition Communication 220 and VIO server LPAR 215.
FIG. 3 depicts Improved Shared Resource 300 using a VIO server
distributed across several LPARs. The LPARs on Improved Shared
Resource 300 are connected by Inter-Partition Communication 320,
just as the prior art in FIG. 2. LPAR_1 311 and LPAR_5 315 run
applications on an AIX operating system. LPAR_2 312 runs
applications on a LINUX operating system. LPAR_3 313 runs
applications on an i5 operating system. LPAR_4 314 has unassigned
resources available for increases in demands for computing
resources. Distributed VIO Tool 400 runs on any of the LPARs, as
part of the overall server management software. LPARs 311, 312 and
315 are physically connected to I/O devices 351, 352 and 353
respectively. Each LPAR (311-315) can access any of I/O devices 350
via Inter-Partition Communication 320 and the direct I/O
connections through LPARs 311, 312 and 315. In an embodiment of the
invention, LPAR 311, 312 or 315 may have a dedicated I/O device
that is not shared by the other LPARs.
Distributed VIO Tool 400 typically is stored in a memory,
represented schematically as memory 420 in FIG. 4. The term
"memory," as used herein, includes without limitation any volatile
or persistent medium, such as an electrical circuit, magnetic disk,
or optical disk, in which a computer can store data or software for
any duration. A single memory may encompass and be distributed
across a plurality of media. Thus, FIG. 4 is included merely as a
descriptive expedient and does not necessarily reflect any
particular physical embodiment of memory 420. As depicted in FIG.
2, though, memory 420 may include additional data and programs. Of
particular import to Distributed VIO Tool 400, memory 420 may
include Autonomic Manager 430, Applications 450, I/O Device Mapping
List 460, and I/O Device Managers 470 with which Distribute VIO
Tool 400 interacts. Additionally, Distributed VIO Tool 400 has
three components: I/O Management Component 500, I/O Device
Assignment Component 600 and I/O Failover Component 700.
Autonomic Manager 430 continuously monitors and analyzes the
computer system to ensure the system operates smoothly. One major
function known in the art for Autonomic Manager 430 is load
balancing so that system resources are efficiently used by
applications on the server. Applications 450 are the functional
programs performing tasks for users on the server. Examples of
Applications 450 include such things as databases, Internet sites,
accounting software and e-mail service. I/O Device Mapping List 460
is a file that maps various applications and LPARs to specific I/O
devices using bindings. I/O Device Mapping List 460 may also
include other configuration preferences such as a performance
threshold for I/O devices or a preferred priority for assigning
certain applications to an I/O device. I/O Device Managers 470 are
programs that configure and operate the physical I/O devices.
As shown in FIG. 5, I/O Management Component 500 starts whenever an
I/O request is made for one of Applications 450 on shared resource
300 (510). I/O Management Component 500 receives the I/O request
(512) and accesses I/O Device Mapping List 460 (514). I/O
Management Component 500 determines if an I/O device has been
assigned to the application or LPAR that made or received the I/O
request (516). If an I/O device is not assigned, I/O Management
Component 500 starts I/O Device Assignment Component 600 (518). If
an I/O device is already assigned, or after assigning an I/O
device, I/O Management Component 500 determines if the assigned I/O
device is available (520). If the assigned I/O device is not
available, I/O Management Component 500 starts I/O Failover
Component 700 (522). After insuring that the I/O request is
assigned to an available I/O device, I/O Management Component 500
determines whether the assigned I/O device is performing at an
acceptable level (524). Performance thresholds may be set in I/O
device mapping list 460, or may come from another source, such as
Autonomic Manger 430. If the I/O device performance is not
acceptable, I/O Management Component 500 starts I/O Device
Assignment Component 600 (526). Once an I/O request is assigned to
an available, acceptable I/O device, the I/O Management Component
500 sends the I/O request to the assigned I/O device manager 470
(528) and I/O Management Component 500 stops (530).
FIG. 6 shows that I/O Device Assignment Component 600 starts when
initiated by I/O management Component 500 (610). I/O Device
Assignment Component 600 reads the I/O request (612) and opens I/O
Device Mapping List 460 (614). I/O Device Assignment Component 600
consults Autonomic Manager 430 to identify performance metrics of
available I/O devices (616). I/O Device Assignment Component 600
assigns the I/O request to the best performing I/O device of the
type needed by the I/O request (618). The assignment of the I/O
device may also be influenced by priority preferences stored in I/O
Device Mapping List 460. I/O Device Assignment Component 600 saves
the assignment to I/O Device Mapping List 460 (620) so that
subsequent requests in the session will already be assigned. Using
bindings to link a request to a specific I/O device allows the
client to encapsulate the assignment in subsequent requests in the
session. I/O Device Assignment Component 600 closes I/O Device
Mapping List 460 (622), sends the I/O request and assignment back
to I/O Management Component 500 (624) and stops (628).
An alternate embodiment of I/O Device Assignment Component 600 (not
shown) does not consult Autonomic Manager 430 or another
centralized tracking and tuning program to make I/O device
assignments. Instead, the alternate embodiment queries each I/O
device manager 470 individually, then makes the assignment based on
the responses of each I/O device manager 470.
I/O Failover Component 700, shown in FIG. 7, starts when initiated
by I/O management Component 500 (710). I/O Failover Component 700
is initiated whenever an I/O request is assigned to a failed or
unavailable I/O device. An I/O device may become unavailable
because the I/O device itself failed or the LPAR connected to the
I/O device has failed. I/O Failover Component 700 receives the I/O
request (712) and opens I/O Device Mapping List 460 (714). I/O
Failover Component 700 consults Autonomic Manager 430 to identify
performance metrics of available I/O devices (716). I/O Failover
Component 700 assigns the I/O request to the best performing I/O
device of the type needed by the I/O request (718). The assignment
of the I/O device may also be influenced by priority preferences
stored in I/O Device Mapping List 460. I/O Failover Component 700
saves the assignment to I/O Device Mapping List 460 (720) so that
subsequent requests in the session will already be assigned. Using
bindings to link a request to a specific I/O device allows the
client to encapsulate the assignment in subsequent requests in the
session. I/O Failover Component 700 determines if any other
applications, LPARs or sessions are assigned to the failed device
(722) by reviewing bindings stored in I/O Device Mapping List 460.
If other assignments to the failed device are identified, I/O
Failover Component 700 assigns future I/O requests for the
application or LPAR to the best performing I/O device (724) and
saves the assignment to I/O Device Mapping List 460 (726). After
reassigning I/O requests, I/O Failover Component 700 closes I/O
Device Mapping List 460 (728), sends the I/O request and assignment
back to I/O Management Component 500 (730) and stops (732).
As with I/O Device Assignment Component 600, an alternate
embodiment of I/O Failover Component 700 (not shown) does not
consult Autonomic Manager 430 or another centralized tracking and
tuning program to determine I/O device assignments. Instead, the
alternate embodiment queries each I/O device manger 470
individually and then makes the assignment based on the responses
of each I/O device manger 470.
A preferred form of the invention has been shown in the drawings
and described above, but variations in the preferred form will be
apparent to those skilled in the art. The preceding description is
for illustration purposes only, and the invention should not be
construed as limited to the specific form shown and described. The
scope of the invention should be limited only by the language of
the following claims.
* * * * *